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Date: Wed, 20 Jul 2011 14:39:23 -0700
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@elte.hu>, Ben Greear <greearb@candelatech.com>,
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Subject: Re: [PATCH rcu/urgent 0/6] Fixes for RCU/scheduler/irq-threads
 trainwreck
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On Wed, Jul 20, 2011 at 11:05:53PM +0200, Peter Zijlstra wrote:
> On Wed, 2011-07-20 at 12:29 -0700, Paul E. McKenney wrote:
> 
> > Peter, does #4 (protect __rcu_read_unlock() against scheduler-using
> > irq handlers) remove the need for #5 (Add irq_{enter,exit}() to
> > scheduler_ipi()) and #6 (Inform RCU of irq_exit() activity)?  My guess is
> > "no" for #5 and "yes" for #6.
> 
> More or less, we want to keep #5 for it does more than just fix RCU, but
> yeah, I _think_ #4 obsoletes the direct need for #6.

Heh.  So the lowest risk is keeping #6 for now and deciding later
whether we really need it.

							Thanx, Paul